蓄电池内阻测量的电池管理系统的设计

蓄电池内阻测量是电池管理系统的一个重要功能,电池内阻值是衡量电池性能的一个重要指标。利用交流注入法实现蓄电池内阻的在线测量,利用锁相放大器 AD630处理小信号电路,提高了测量精度,测量误差小于10％;通过RS485实现数据交换,便于集成于其他系统,满足用户多方面的需求;并设计了电源回路,测量系统的电源可由被测量电池提供,也可由外部电源提供。     

变电站蓄电池支持向量机建模在线监测研究

针对广泛应用于变电站储能的蓄电池,提出了一种新的蓄电池内阻在线检测技术。为了在线获得蓄电池性能,采用了支持向量机建模技术的变电站蓄电池性能在线监测方法,该方法综合了交流阴抗法和直流放电法的特点。充放电池实验数据作为最小二乘回归支持向量机的初始建模数据,从而得到基于交流阻抗法的蓄电池内阻模型和剩余容量模型。使用蓄电池运行过程中的核对性放电数据和瞬时放电数据作为回归模型的在线校正数据。基于该方法的变电站蓄电池在线监测系统已在变电站使用了4年以上,故障模拟和实际运行表明该方法能有效辨识已劣化电池以及预测电池性能的变化趋势。     

智能蓄电池系统在电力调度自动化主站中的应用

本文介绍了常用的蓄电池监测方法和智能蓄电池组监测系统的应用。该系统可应用于各种蓄电池组的性能监测,综合判定蓄电池组的性能,有效地活化蓄电池的使用寿命,并能对失效的电池给以报警提示。     

大容量蓄电池内阻测量的虚拟仪器研制

蓄电池内阻是评估蓄电池性能的一个重要指标,实现单体电池内阻的在线实时监测,对提高直流系统的安全运行、提高供电系统的可靠性和自动化程度,有着十分重要的意义;系统采用四线交流法进行测量,将虚拟仪器技术应用于蓄电池内阻测试,详细介绍了该装置的工作原理及硬件和软件的设计;测量仪分为4个档位,测量时由PC机自动换档,实现了仪表的智能化;该系统具有测量精度高、抗干扰能力强、可实现在线测量等优点,具有良好的实用价值和推广意义。     

电视发射机房UPS蓄电池远程在线监测管理系统

针对分布式电视发射机房的UPS蓄电池监测和维护难的问题,设计了蓄电池自动在线监测管理系统,该系统由检测终端、通信网络、监测中心服务器和浏览器客户端组成;检测终端采用嵌入式处理器ARM2440作为核心控制器,通过互感器测量电池浮充和放电状态的电压及电流,根据得出的单体电池内阻诊断健康状态;检测测终端与监测中心服务器采用C/S架构设计,通过建立TCP/IP网络连接将电池组的各种参数和运行状态数据上传到远端服务器进行处理、分析、显示、存储和在WEB上发布;经实验证明,该系统测量精度高、工作稳定,能及时准确甄别出存在于电池组中的劣化电池,实现了蓄电池的在线检测和集中管理。     

基于浮空总线的蓄电池组监测传感器的研制

针对大型蓄电池组维护难的问题,提出了采用总线浮空的设计方法.研制了一种在线式的蓄电池组监测传感器,将每节蓄电池单元的电压、温度、内阻数字化实现实时在线测量,从而及时发现失效的电池单元.同时给出了监测传感器的结构、原理和硬件系统的设计.与采用模拟信号隔离的集中监测设计相比,该设计具有更好的可靠性、采集精度、安全性和稳定性,且成本低、体积小,具有良好的工程应用前景.     

变浆系统后备电池在线监测及电压均衡系统以及方法

本论文是关于一种变浆系统后备电池在线监测及电压均衡系统以及方法,特别是涉及一种大型风电机组的变浆系统后备电池在线监测及电压均衡系统以及方法。其不仅可以及时、准确地监测蓄电池组中每节电池的具体参数,依此在远端的监控主机上对变桨控制器进行对应的操作,而且在监测的过程中通过对各个蓄电池组单体进行电压均衡操作,使蓄电池组长期处于健康稳定的状态。     

蓄电池内阻检测系统设计

论文分析了蓄电池内阻的组成及测量方法,根据其特点采用交流注入法在线测量蓄电池内阻,说明了其工作原理。运用锁相放大法对蓄电池内阻进行测量,选用以TI公司的DSP芯片TMS320F2812为控制核心,设计了由锁相放大器、滤波、差分放大以及AD630平衡调制解调器等单元构成的蓄电池内阻检测系统,此系统易于和计算机相连,形成一个自动的检测网络。还能有效地抑制了噪声和干扰,并简化了设计。     

蓄电池远程管理维护系统研究与设计

蓄电池管理系统采用物联网、移动通信、集成芯片等技术，可以实时的采集和分析蓄电池的运行状况，从而能够实现蓄电池的运行管理和维护更新。本文结合地铁站蓄电池管理需求，设计一个蓄电池远程管理维护系统，该系统采用分布式的架构，能够详细地展示电池运行数据，比如电压、内阻、温度等，基于电池运行数据进行综合分析，从而可以在线判断电池容量可靠性，及时准确发现电池各类隐性故障，同时监控电池的单体承载，均衡蓄电池的实际容量，避免过度依赖某一单体电池产生恶性循环，进一步调了电池维护的智能化和自动化。     

基于CAN总线的蓄电池智能监测系统

介绍了一种具有CAN总线接口的蓄电池在线监测系统,采用两级网络结构,以Cygnal公司的C8051F045微控制器为测量系统的核心,实现测量控制、数据处理、参数设置、显示报警、通讯等功能,底层是以智能监测芯片DS2438构成的检测板,安装在每只蓄电池上,负责蓄电池电压、电流、温度等参数的在线采集,通过单总线与微控制器通讯;C8051F045通过CAN总线与监控主机通讯,实现了蓄电池的远程实时监测和管理,保障了蓄电池的可靠工作.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).